Hydrocarbons in the form of petroleum deposits and crude oil reservoirs are distributed worldwide. These oil reservoirs are measured in the hundreds of billions of recoverable barrels. Because heavy crude oil has a relatively high viscosity and may adhere to surfaces, it is essentially immobile and cannot be easily recovered by conventional primary and secondary means.
Use of surface active agents or surfactants to increase solubility of oil through reduction in surface and interfacial tensions is another technique for increasing crude oil recovery. A wide variety of surfactants identified thus far are able to significantly reduce surface and interfacial tensions at oil/water and air/water interfaces. Because surfactants partition at oil/water interfaces, they are capable of increasing the solubility and bioavailability of hydrocarbons (Desai and Banat (1997) Microbiol. Mol. Biol. Rev. 61: 47-64; Banat (1995) Bioresource Technol. 51:1-12; Kukukina et al. (2005) Environment International 31:155-161; Mulligan (2005) Environmental Pollution 133:183-198). For example, Doong and Lei ((2003) Journal of Hazardous Materials B96:15-27) found that the addition of surfactants to soil environments contaminated with polyaromatic hydrocarbons increased the mineralization rate of some hydrocarbons.
U.S. Pat. No. 4,404,109 discloses the production of microemulsions in the presence of aqueous saline solutions using a co-surfactant and a surface-active agent that is an N-acyl alpha-amino acid salt having a relatively long-chain aliphatic or alkylaryl (C6 to C120 chain) group on the central amino acid carbon and a C1 to C18 chain as part of the N-acyl group.
There remains a need for additional chemical compounds that are biodegradable and have low toxicity, which may be used to release oil from hydrocarbon coated surfaces for improving oil recovery.